A heat pipe for a semiconductor that is used for cooling a power transistor generally is composed of pipes, fins mounted at one end of the pipes so as to serve as a heat dissipation section, semiconductor mounting metal blocks mounted at the other end of each pipe so as to act as a heat absorption section, and insulation cylinders positioned at the intermediate portion of the pipes, to connect the pipes to each other, as disclosed in Japanese Patent Application (OPI) No. 293654/1987. In the so-constructed conventional heat pipe, heat generated from the semiconductor is transferred through the metal block to the heat pipe and is transferred to the fins of the heat dissipation section by the heat pipe effect. This results in the heat being outwardly dissipated or discharged by natural convection and/or forced convection by a fan or the like.
In recent years, a semiconductor of a high density and a mass storage capacity has been proposed and manufactured. The development of such a semiconductor creates a need for a cooling apparatus capable of exhibiting better cooling efficiency to cool the semiconductor.
Conventionally, a water-cooled-type cooling apparatus has been used for directly cooling a semiconductor. The water-cooled cooling apparatus is generally constructed in such a manner as shown in FIG. 7. More particularly, in the cooling apparatus, a metal block 49, of satisfactory thermal conductivity for mounting a semiconductor is provided therein with a passage 50 for cooling water, so that cooing water is guided from an inlet nozzle 51 through the passage 50 to an outlet nozzle 52, to cool a transistor 53 that is generating heat. Unfortunately, the water-cooled-type cooling apparatus is low in cooling efficiency, resulting in an inability to meet the recent requirements for cooling a semiconductor.
An improvement in cooling efficiency of the cooling apparatus requires increasing the length of the passage 50. For this purpose, an approach is proposed in which, as shown in FIG. 8, a passage 55 in a metal block 54 is provided to form a plurality of meandering flows. In FIG. 8, reference numerals 56 and 57 each designate a nozzle and reference numeral 58 designates a semiconductor.
However, the formation of the passage 55 in the metal block 54 requires much labor and time due to its complicated construction, leading to an increase in manufacturing cost. Also, there was a limitation of cooling efficiency even by this improvement. Thus, the water-cooled-type cooling apparatus fails to not only contribute to manufacturing of a semiconductor of a high density and of a mass storage capacity but also to provide a semiconductor with satisfactory electrical insulation.